It is known to provide an inflatable restraint system in a vehicle to augment protection traditionally afforded vehicle occupants through the use of seat belt restraints. In some vehicles, the inflatable restraint system may be an air bag system disposed within an occupant compartment in the vehicle in close proximity to either a driver occupant or one or more passenger occupants. Typically, the air bag system includes an air bag module attached to vehicle structure such as a steering wheel and having an air bag for deployment through an opening in a cover to extend in the occupant compartment of the vehicle. The deployed air bag restrains movement of the occupant to help protect the occupant during a collision.
Various mounting mechanisms have been used for securing the inflatable restraint module to a support structure in a vehicle, such as a steering wheel or dashboard. In one known mounting mechanism, mounting bolts are provided passing from a rear of the support structure and threadably engaging nuts mounted on the inflatable restraint module. In another known mounting mechanism for a vehicle steering wheel, sleeve members mounted to the inflatable restraint module and surrounding the mounting bolts may be forced into contact with a plate forming the supporting structure on a hub portion of the steering wheel to complete a circuit for actuating a horn.
An example of a mounting mechanism for an inflatable restraint module is disclosed in U.S. Pat. No. 5,380,037 to Worrell et al. In this patent, a mounting mechanism is used in mounting an inflatable restraint module to a support structure such as a hub portion of a steering wheel. The steering wheel has a support plate attached to the hub portion and opposing front and rear faces with a plurality of apertures therethrough. The inflatable restraint module has a plurality of mounting members that are adapted to pass through and be retained within the apertures in the support plate. Each of the mounting members is individually cold-formed and broached into a solid, round steel pin having a head portion and an opposing distal end. Each of the head portions of the mounting members, typically four, must be separately pressed or welded onto a metal base plate. Each of the mounting members includes a slot for receiving a spring that traverses across the apertures of the support plate. The spring is a flat wire spring. Due to the limited bending moment available, this flat wire spring has a high bending moment, resulting in increased insertion efforts required to assemble the air bag module, e.g., approximately eighty newtons (80 n), to the support plate of the steering wheel.
As a result, it is desirable to provide a mounting mechanism for an inflatable restraint system having reduced or lower insertion effort of an inflatable restraint module to a steering wheel. It is also desirable to provide a mounting mechanism for an inflatable restraint system with a snap-on design and improved durability.